Motor fuel synthesis



Sept. 18, 1945.

D. cARMoDY ETAL MOTOR FUEL SYNTHESIS Filed June 19, 1943 mnhmk v :Quangfnyenor'; 3er-narra H Shoemaker D07?` R. Carmoqy @y aM/MM@ y orneyPatented Sept. 18, 1945 lUNITED STATES 2,384,796 PATENT OFFICE MOTORFUEL SYNTHESIS Don R. Carmody, Newton, Iowa, and Bernard H.

Shoemaker,

Standard Oil Company tion of Indiana Hammond, Ind., assignors toChicago, Ill., a corpora- Application June 19, 1943, Serial No. 491,486

- 7 claims.` (Cl. 44-53) polymerization or alkyla-tion process whenpetroleum renery gas is contacted with phosphoric acid catalyst. Anotherobject of the invention is to effect simultaneous polymerization,alkylation and etherization reactions in a single catalytic conversionzone, thereby producing a fuel containing hydrocarbons and ethers ofhigh knock rating suitable for aviation motor fuel and particularlycharacterized by high knock rating under supercharging conditions ofengine operation.

shows diagrammatically an apparatus suitable for carrying'out theprocess. Referring to the drawing, a gaseous hydrocarbon feed stockwhich may be isobutlyene, or mixtures of propylene and is introduced byline I to reactor i I. The hydrocarbon feedis preferably supplied inliquid form and at sufcient pressure to maintain it in liquid phase.Pressures of 150 to 500 pounds per square inch are usually .sufllcientcharged with the phosphoric acid catalyst, for example, granular, porouscatalyst made by adsorbing phosphoric acid on kieselguhr, silica'gel,active carbon, etc. The catalyst is maintained at a temperature of about100 to 350 F., preferably about 250 to 300 F. Some steam or water may beintroduced with the feed to maintain the catalyst at the proper state ofhydration.

Simultaneously with the introduction of the hydrocarbon gas thru line'l0 there is also introduced a stream of methanol by line |21 In thepresence of the catalyst the methanol is found to react with the olefinhydrocarbons producing various ethers of highly branched structure, one

of which is .methyl tertiary butyl ether. The reaction product is passedby line I 3 to scrubber I4 where any unre'acted methanol anddimethylether is absorbed by a current of wash liquid for example1 waterintroduced by line I5. The wash liquid withdrawn from the base of thescrubber by line I6 passes' to stripper I'I where methanol `and methylether are driven oil thru vapor line I8 leading back to reactor II..'I'he Wash Water employed in the scrubbing may be discarded at I9 orrecycled by line '2U back to the scrubber I4.

The motor' fuel product 1s conducted `by line 2| vn,-flandowner.zr inwhich a light 'fraction containing principally normal and isobutane hydroearbons isirempvec *thru .vapor une 23 1ead ins to fractionator24g-wherein the normal butane 25 butylenes, or a C4 fraction of crackingstill gas The reactor il is is removed as a bottom fraction thru line 25and isobutane is taken overhead thru line 26. The

isobutane may be discarded from the system by valved outlet 2l orrecycled by line 28 leading 5 back to reactor I I.

,lfiinic ingredients are hydrogenated in the presence of a hydrogenatingcatalyst and gaseous hydrogen. The hydrogenated product is thenconducted by line 33 to fuel st rage tank 30.

When the hydrocarbon from cracking operations it will contain all of Ithe C4 hydrocarbons in varying amounts including particularly isobutane,isobutylene and normal butylene. In the presence of methanol introducedthru line I2, 'the isobutylene is preferentially converted to methyltertiary butyl ether, a very desirable motor fuel ingredient. Thecatalyst is thereafter permitted to react with the normal butylene`converting it into branched- 3 chain butylene polymers boiling largelywithin the motor fuel boiling range, or effecting an alkylation reactionbetween the normal butylene and the isob'utane which is present. We mayalso intraduce benzene (CSHG) into the reaction con- 5 jointly with theOlean gases and methanol. Un

der the conditions of alkylation and etherization existing in reactor IIthe benzene is largely alkylated to substituted benzenes characterizedby a desirable knock rating;- particularly in aviation motor fuel. Wherepropylene is present in the feed stock with benzene, the benzene will bepreferentially alkylated to cumene.

' As an; alternative of the process described above. we may employ apetroleum hydrocarbon fraction containing propylene and butylenes towhich is added the desired amounts lof benzene and methanol. When thisfeed is processedwith a phosphoric acid catalyst under the conditionsdescribed above we obtain a fuel rich in isoproknock characteristics.

It -is generally desirable that the ratio of benzene to oleflns be ofthe order of 0.5:1 up to 2:1

mol ratio. Methanol may be charged in suilicieni; amount to equal themolar concentration of isobutylene,A allowance being made for methanolrecovered from stripper I1. l It is not necessary to obtain completeetherization of isobutylene by the eed stock admitted to m) the processby line I0 is a refinery C4 fraction The invention is illustrated by adrawing which methanol because any unetherized isobutylene 1Ssubsequently converted before leaving the catalyst bed in reactor H toother desirable products such as isooctene or, when benzene 1s presenttertia butyl benzene.

In this rzpplication the term readily alkylatable hydrocarbon is .usedto' include the leoparalhns such as isobutane and the light aromatichydrocarbons such as benzene.

By recycling isobutane by line 28 a higher concentration of thishydrocarbon may be maintained in reactor I l thereby increasing thealkylaton of olenes andreducing the amount of butylene: dimer producedin the reaction. For this purpose it is generally desirable to maintainthe mol ratio of isobutane to n-butylene in the range -o about 2 to 5.When benzene isemployed as a 'component of the feed stock theconcentration of isobutane may be reduced and'sobutane may be preventedfrom building up in the system to an excessive amount'by discarding itthru valved line 21. Any dimethyl ether not removed in scrubber l willappear with C: and C4 hydrocarbons in line 2t and maybe recycled.

The temperature of reactorv H may be main'- tained in any conventionalmanner by heating coils or by preheating the stock charged thereto.Although' water has been described as a scrubhing medium for use inscrubberi to recover 'methanol and methyl ether from the reactionproducts, other suitable absorption liquids may be employed for thepurpose, for example butyl alcohol, glycerin, glycol and water solutionsthereof. The carryover of a small amount of water thru line I8 intoreactor tl' is generally advantageous rather ythan dlsadvantageous tothecatalyst. As an example of the operation of our process as applied tcthe treatment of isobutylene and methanol, th'e following runs weremade: A mixture of isobutylene and methanol in the ratio ci 1.3 mols ofthe former to l mol' oi the latter was passed over a catalyst comprisedof phosphoric acid on kieselguhr at a pressin'e of pound-s per vsquareinch under the following conditions:

Run No.

Reaction temperature, F

All products of the above runs are characterized by high knock rating'above 190 octane'number CFR motor method. Flow rates of about 0.65 to 1gallon of liquid feed per hour catalyst are usually satisfactory.

One of the important features of our process is th'e con-version of amixed C4' hydrocarbon stream into liquid products boilingl in theaviation gasoline boiling range in such a. way that the maximum knockrating is obtainable. This we have accomplished by avoiding dimerizationof isobutylene, by effecting its etherization with methanol while normalbutylene is simultaneously alkylated with other hydrocarbons, preferablyisobutane and bmi-zene yielding alkylation products with desirable highknock rating and high supercharged performance.

Another feature of the invention is the advantageous effect of methanolon the phosphoric acidcatalyst, increasing its life and eiilcency inhydrocarbon conversion.

mally gaseous aleen to the action of a phosphoric acid catalyst underalkylating conditions and simultaneously introducing methanol into thereaction, thereby facilitating the alkylation of said isoparaiiinhydrocarbon and producing ethers, resulting in a motor fuel productcontaining both alkymers and methyl ethers.

v2. Theqprocess of claim l wherein said normally gaseous `olein isisobutylene and thev amount ofv methanol employed is substantially equalto the amount of isobutylene on a molar basis.

`3. The process of claim 1 wherein the reaction is conducted at atemperature ofabout 109 to 350 F.

4. The process of making high knock' rating motor fuels which comprisessubjecting a mixture of an isoparaln hydrocarbon, normal butyiene andisobutylene to the action of a phosphoric acid catalyst under alkylatingconditions at a. temperature yof about 100 to 359 F., and simultaneouslyintroducing into said catalyst a stream of methanol whereby saidisobutylene is converted to methyl tertiary butyl-ether and said normalbutylene is converted to an alkylation product with said iscparainhydrocarbon.

5. The process of making high knock rating motor fuels which comprisessubjecting a mix- .of alkamers and ethers ture of isobutane, normalbutylene and isobutylene to the action of a phosphoric acid underalkylating conditions at elevated temperature and simultaneouslyintroducing into said catalyst a vstream of methanol whereby' saidisobutylene is converted to methyl tertiary butyl ether andl said normalbutyiene is convertedto an alkylation product withisobutane.

6. The process of making high mock rating motor fuels which comprisessubjecting an unsaturated C4 fraction of refinery sas containingisobutane andv both isobutylene and normal butylene to the action of aphosphoric acidcatalyst underV alkylating conditions at a. temperatureof about 250 to 300 F., 'simultaneously introducing into said reactionaI s of methanol in an amount suillcient to etherize the isobutylene butlnsumcient. to etherize the normal butylene contained in said C4hydrocarbon fraction, continuing the reaction until said isobutane issubstantially alkylated in the presence of said acid and methanol 'andseparating from the reaction' a motor fuelv consisting-essentiallyboilinsr in the motor fuel boiling range. 7. The process of making highknock rating motor .fuel which comprises subjecting a mixture of anisoparaiin hydrocarbon and an 'olefin hydrocarbon to the action ,of aphosphoric acid catalyst under alkylating conditions at a temperature ofabout 256 to 300 F; and simultaneously introducing into said reactionmixture a stream of methanol whereby said olefin hydrocarbon is partlyalkylatcd with said isoparamn and partly converted into a methyl-etherderivative and recovering the mixed reactionproduct for use as said,high knock rating motor fuel. f DON R. CABMQDY.

BERNARD- H. SHO..

CERTIFICATE OF CORRECTION. Patent No. 2, 5815796. i I September 18",1914.5.

DON R. CARMODY, ET lAL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second column; lireA 58, claim 5, after the words "phosphoric acidinsert -A--ca'calyst--g and that the said Letters Patent should be readwith this correction therein that the same' may conform to the record ofthe oase in the Patent Office. y y

Signed and sealed this Lith day of December, A. D. 1911.5.' l

Leslie Frazer` v (Seal) First Assis tant Commissioner of Patents.

